1. Field of the Invention
The present invention relates to an apparatus for controlling power generated by a generator mounted in a vehicle, such as passenger vehicle and commercial vehicle.
2. Description of the Related Art
A conventional generator mounted on a vehicle is accompanied by a generation controller, which controls the generation activities of the generator.
Such a generation controller is shown; for instance, by Japanese Patent Laid-open Publication No. 2002-325085. This publication exemplifies a generation controller which operates in response to a command from an ECU (electrical control unit) disposed outside the generator. Specifically, when the generation controller fails in reception of a command signal from the ECU or does not receive a command signal over a plurality of intervals in succession or during a predetermined period of time continuously, the generation controller takes an action against such failures. That is, when such failures occur, the generation controller operates such that a characteristic value set based on the received command signal is forcibly set to a default value. Using this generation controller, it is possible to control the on-vehicle generator in its normal conditions, even when some accidents are caused on the command signals transmitted and received to and from the ECU via a communication line.
However, the default-use countermeasure taken by the above generation controller is still insufficient for an occasion where the values themselves of the commands from the ECU are erroneous. For instance, a calculator, memory, or external sensors included in an ECU to calculate an optimum voltage of power to be generated may be in failure. If such a case occurs, an erroneous command consisting of information codes different from a desired command value is produced and transmitted to the generation controller. Thus an on-vehicle generator is obliged to undergo control based on the erroneous command. One example is that an erroneous command is “a command for generation of zero-volt power.” If information codes indicative of such an erroneous command are transmitted, the generation controller is forced to stop its generation and to hold its non-generated state, which will cause a lack in charging an on-vehicle battery during a vehicle's running state. Hence there is a possibility that various devices electrically connected to the battery are obliged to stop their activities.